The latest instalment in Alesis' classic effects series, the MIDIverb III, is something of a cross between an upgraded MIDIverb II and a cut-down Quadraverb - it includes four effects sections which can be used simultaneously, but doesn't quite have the power or flexibility to stand on a par with the Quadraverb. On the other hand, it is fully programmable and offers more effects facilities than the MIDIverb II, and is therefore a major step forward in this respect.

The MIDIverb III comes in a standard 19" rackmount case, and is supplied with an external power supply. There is no power switch, so you either have to switch power off at the mains or pull out the adapter plug if you want to turn the unit off. The front panel sports three knobs, for Input, Output and Mix levels. These are global controls, determining levels for all effects Programs. Next to these are Signal and Clip LEDs, and a three-digit LED display. Obviously, such a display is not very informative in the context of editing numerous parameters, but programming the MIDIverb III is kept fairly simple by restricting the number of user parameters for each of the four sections to two. To the right of the display are several pushbuttons controlling Program selection and editing. Two red LEDs alongside the effects selection buttons help you to keep track of which parameter is currently selected and displayed.

The MIDIverb III holds 200 effects Programs in its internal memory. Numbers 00-99 are ROM Programs which cannot be overwritten; those numbered 100-199 are duplicates of the ROM Programs when the unit is shipped, but they can be edited and overwritten by the user. The rear panel incorporates left and right channel input jacks, left and right output jacks, and MIDI In and Out/Thru sockets. A fifth jack allows a footswitch to be connected to provide an effects bypass facility, which is also available via a front panel button.

FOUR EFFECTS AT ONCE

Effects Programs in the MIDIverb III use four effects sections; Reverb, Delay, Chorus and EQ. The signal path through these sections is determined by which of 15 Configurations is selected - so, for example, in Configurations 1 through 6, the output of the Chorus section is routed to the stereo outputs without any further processing, as well as providing an input to the Delay section. In other Configurations, however, the chorused sound may only be heard after processing by the Delay and Reverb sections. The choice of Configuration imposes some restrictions on effects sections: only numbers 14 and 15 allow the maximum delay time of 490ms (just under half a second) to be used, but this extra time is bought at the expense of completely removing the Reverb section from the Configuration. Here's what the various effects sections have to offer...

EQ: The EQ section is the same in all 15 Configurations. Two single-pole 6dB per octave low pass filters are available, one to process the input signal and one to process the effected signal - the two parameters are therefore simply called Input and Effect, and select a cut-off frequency for each filter. The filter can be turned off entirely, or the cut-off frequency varied from 13.8kHz down to 160Hz in 31 steps. The Effect EQ damps high frequencies in the reverb decay in all Configurations except 14 and 15, where it affects the regenerated repeat echoes.

CHORUS: The Chorus section offers both chorus and flanging effects. The first parameter is Chorus Algorithm, which determines which of 24 different types of flange/chorus is selected. There are six algorithms in each of four categories - Chorus, Stereo Chorus, Flange and Stereo Flange - and Off can also be selected, if you don't want any chorus at all in a Program. Although the only other parameter here is Speed, the 24 algorithms cover most of the ground occupied by the variations that the user might create with feedback and depth controls.

DELAY: Two parameters are available to control delay effects - Delay Time and Regeneration. In Configurations 14 and 15, the maximum delay is 490 milliseconds, allowing simple mono delay effects to be created, although no reverb is available when the full delay time is operational. In all other algorithms, reverb can be used simultaneously with delay, but the maximum delay time is reduced to 100ms. This is too short to allow any kind of useful delay-only effects to be created, but is very suitable for providing reverb pre-delay.

REVERB: The two adjustable parameters here are Reverb Algorithm and Reverb Decay. 20 algorithms are available: Room 1-4; Hall 1-4; Chamber 1-4; Plate 1-4; Gate 1-2; Reverse 1-2. The maximum decay time varies from one algorithm to another, but is well over 20 seconds in some. The different algorithms simulate acoustic spaces of varying sizes, with a wide range of characteristics in their density and diffusion. Overall, they sound very clean but seem to lack the depth and spaciousness of the Quadraverb's reverb effects. Nevertheless, a very respectable sound. Although a simple choice of algorithm and decay time doesn't offer much room for sonic manoeuvring, the use of the Delay section to provide pre-delay and Effect EQ to tailor the reverb's high frequency response adds a good deal to the user's control over the reverb sound.

MIX: Finally, a Mix section allows you to set a balance oetween the reverb and delay effects, with parameters available for controlling Reverb and Delay levels. The Chorus level is always the same, and is either on or off, depending on your choice of Chorus algorithm.

REAL-TIME MIDI CONTROL

A very important facility which the MIDIverb III has inherited from the more expensive Quadraverb is that of real-time MIDI control of effects parameters. For each of the 200 Programs, a routing patch can be defined which allows a single source of MIDI data to control a single destination. The choice of sources includes: Pitch Bend; Modulation Wheel; Aftertouch; Note Number; Note Velocity; Sustain Pedal; Breath Controller; Volume Pedal. Destinations include: Reverb Decay; Delay Time; Delay Regeneration; Chorus Speed; Reverb Level; Delay Level.

On a more mundane level, a MIDI Receive Channel can be set as a global parameter, and you can select effects Programs remotely with MIDI Program Change messages (from a sequencer or synth perhaps). A Program Map is provided to handle the problem of how to select any of 200 Programs with Program Change numbers that only run from 0-127.

IMPRESSIONS

The MIDIverb III occupies the ground between the MIDIverb II and the Quadraverb (both good benchmarks in the field of digital effects) very well. It offers more effects and a better quality sound than the MIDIverb II, and adds full user programmability and real-time MIDI control, but despite its four-effects-at-once capability it does not offer serious competition for any of the multi-effects processors currently on the market at around £500.

However, as its name implies, the MIDIverb III is not intended to compete in this category. It's an excellent programmable reverb unit that happens to be able to throw chorus, EQ and a little delay into the mix - and the results sound beautiful. If you can afford the extra £90 or so to stretch your budget to a Quadraverb, then that unit's versatility and full bandwidth should prove very tempting; but otherwise, apart from Yamaha's £349 FX500, there's really no competition for the MIDIverb III.

FURTHER INFORMATION

£365 inc VAT.

Sound Technology plc, (Contact Details).